#include "stdio.h"
#include "math.h"
int main(){
    int n,i,k;
    scanf("%d",&n);
    k=sqrt(n);
    for(i=2;i<=k;i++){
        if(n%i==0) break;
    }
    if(i<k) printf("%d is not a prime number",n);
    else printf("%d is a prime number",n);
}